Having worked for Best Buy mobile in the past, I would be leary. You may pre-order and arrive at the store and wait for an hour just to find that even though you got an email saying its in store, its nowhere to be found. Last year I ended up buying a 64gb due to the fact they didn't have the original even though I got the email saying its ready.
They always fumble launch day. But, if that's the only choice you have, go for it!
EDIT: if you want a firm delivery/available date, go with Apple or a carrier.